A control type magnetic bearing is known as the most general type of a non-contact thrust bearing. For example, there is a control type magnetic bearing so constituted as to support a rotor by a bearing that utilizes an electromagnet as shown in FIG. 5(a), or a control type magnetic bearing having a constitution as disclosed in Non-Patent Literature 1. There is also a bearing that utilizes superconductivity. The bearing developed utilizes superconducting bulk and a permanent magnet. For example, there is a bearing provided with a permanent magnet under a rotor, and the permanent magnet is disposed to face superconducting bulk, as shown in FIG. 5(b) (see also Patent Literature 1). There are also bearings having a constitution as disclosed in Non-Patent Literatures 2 and 3.
Non-Patent Literature 1: “KOYO Engineering Journal No. 158 (2000)”, KOYO SEIKO CO., LTD., printed on Jul. 23, 2000), pages 16 to 20
Patent Literature 1: Unexamined Japanese Patent Publication No. 2001-343020
Non-Patent Literature 2: “KOYO Engineering Journal No. 156 (1999)”, KOYO SEIKO CO., LTD., pages 9 to 14
Non-Patent Literature 3: “KOYO Engineering Journal No. 151 (1997)”, KOYO SEIKO CO., LTD., pages 12 to 16